Advantage:1.Mirror designed Stainless steel 430 with thickness 1.2mmbalde,never distortion and broken, the angle of the blades is patented designed.2.Hot-Galvanized steel sheet ,the layer of galvanizations more than180 g/m2, one-off moled frame.3.experiment of homeostasis make the blade work smoothly,nearly no noise and steadily output of air.4.Belt pulley are aluminium magnesium alloy injection moulded ,light and high-strength.5.Adopt auto belt-tensioner which can adjust the loose or tighten of belt and never drop.6.Imported france bearing with long service life.